BLOCKS; At Ground Zero, a Conduit of People and Memory

Almost every other architectural feature in the rebuilt PATH station at the World Trade Center will be different. But that sweeping array of eight parallel escalators linking the mezzanine to the concourse 35 feet above -- really the defining architectural feature of the old station -- will be piercingly familiar.

How extraordinary, in a landscape so transformed, to come upon this surviving spatial recall of the World Trade Center, this three-dimensional memory of a world that ended on Sept. 11, 2001, after passengers were evacuated from a seven-car Hoboken train on Track 3.

Though the new PATH station is six or seven months from reopening, it has already taken discernible form. One can begin to experience the space as it will be, especially since the finishing touches are not going to change it much. The gray steel beams, columns and X braces will be left exposed, as will the underside of the corrugated floor decking.

The station will not be heated or air-conditioned. There will be only one newsstand and little advertising. No windows in the station will open on to the 70-foot-deep ''bathtub'' in which it sits.

This PATH station is not meant to be contemplative. Or permanent. Though some of the structure will eventually be reused, it is now more of a conduit for 55,000 passengers, a stopgap until an ambitious new transit center is built. Its purpose, said Joseph J. Seymour, executive director of the Port Authority of New York and New Jersey, ''is to restore transportation that's been severed.''

Yet, as the first public portal at ground zero, the station is necessarily symbolic, whether intended or not.

In its branching form, the station's 25-foot-high Church Street canopy, designed by Robert I. Davidson, the authority's chief architect, might come to be seen as a steel sprout, the first shoot of renewed life to emerge above ground.

In the lack of finish, the station interior will convey the accurate impression that the future of the trade center site is far from decided.

In its diffidence toward its surroundings, the station will reflect the tremendous popular ambivalence about the site; a mass graveyard that is now the linchpin in the redevelopment of Lower Manhattan.

In orientation, with only a single entrance at Church Street, the station turns its back on Battery Park City. To get there, commuters will have to funnel off to Vesey or Liberty Street and cross West Street. Mr. Seymour said there was no alternative for the time being, since the entire area around the station is, or soon will be, under construction. But an escalator is to be added at the Liberty Street pedestrian bridge, and an additional pedestrian bridge is to cross West Street at Vesey Street.

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As a matter of fact, it will still be known as World Trade Center. When PATH officials were asked if that name ought to be reused, Mr. Davidson said, they answered, ''What else would you call it?''

Trains will still cross the river through cast-iron tubes completed in 1909 for the Hudson & Manhattan Railroad Company, predecessor to PATH. The two tubes survived 40 days of flooding after Sept. 11 -- ''It was biblical,'' said Anthony G. Cracchiolo, director of the authority's priority capital programs -- but required new tracks, power lines and signals as part of a $544 million reconstruction project, which also includes repairs to the Exchange Place station in Jersey City.

THE World Trade Center station will still have five tracks and three platforms. (Two cars from the abandoned Hoboken train were salvaged and taken to Kennedy International Airport, where they are stored with other artifacts of the attack, said Peter L. Rinaldi, general manager of the trade center site in the priority capital programs unit.)

Above the platform level, a 22-foot-high mezzanine stretches 416 feet by 140 feet; that is slightly more floor area than the main concourse at Grand Central Terminal. Even in a raw-edged state, it is an imposing volume. Now open at the sides, the mezzanine may be enclosed in translucent vinyl screens or fiberglass boards, possibly imprinted with famous quotations about New York.

It will also house the single work of art in the station: a 118-by-13-foot mosaic mural designed by Giulio Candussio of the Scuola Mosaicisti del Friuli in Spilimbergo, Italy, northeast of Venice, where it is being fabricated. The mural is a gift from the regional government of Friuli-Venezia Giulia.

Titled ''Iridescent Lightning,'' it is composed of a gigantic jagged bolt running the length of the wall, varying in color from fiery bursts of red and orange to cooler strands of green and blue. Full of peaks and valleys, it is meant to capture the energy and continuity of life.

But there will be no more vivid evocation of continuum than the unmistakable 58-foot-wide escalator bank, where the machinery is new but the space is almost unchanged. For an instant, as commuters face that silvery mechanical cascade again, it may feel as if the world itself is unchanged.